As used herein, the term "continuous filament" or "continuous filament yarn" refers to fibers of indefinite or extreme length.
The terms "harsh nodes", "node harshness", and "yarn harshness" are as defined in U.S. patent application Ser. No. 07/619,377, now allowed, which is incorporated herein by reference.
The term "cohere" means to stick or hold together in a mass.
The term "blend" means to mix thoroughly so that constituent parts become nearly indistinguishable.
The term "moresque" refers to a multicolored yarn formed by twisting or plying single strands of different colors or a carpet made from such a yarn. Moresque carpet shows distinct medium to large color spots (about 1/8-1/4). This is in contrast to heather carpet, which is made from single strands which are blended to give the impression of more uniform color.
The term "berber" refers to a carpet style with a distinctly colored bundle of strands in combination but not blended with the majority of fibers or base yarn.
One type of textured BCF yarn contains nodes or compact sections separated by bulky or unentangled sections such as shown in U.S. Pat. No. RE. 31,376 to Sheehan et al. Such yarns with compacted nodes and bulky or non-entangled sections are referred to herein as "interlaced".
U.S. Pat. No. 4,993,218 to Schwartz et al. describes another type of textured BCF yarn which has two different lengths of unentangled sections randomly separating compact sections.
As is known in the art, a carpet with a heather appearance may include small points of individual color randomly distributed throughout a matrix of contrasting colors. Heather BCF yarns can be made from differentially dyeable or precolored component yarns in various ways to provide a variety of heather appearances. These heather appearances can range from a very bold heather with relatively large (up to 1/8) random sections of individual color to a very fine (as small as 1/100") heather having a high degree of yarn-to-yarn filament commingling between the components.
Due to the high popularity of BCF moresque or berber yarns in the carpet market, distinctive novel yarn effects are in high demand. However, the preparation of acceptable new yarns has remained difficult due to the necessity of combining the component yarns in a sufficiently random yet consistent manner to obtain a distinctive and desirable appearance. Much of the difficulty in producing distinct moresque and berber yarns is the need to prevent the formation of directional carpet appearance or patterns, such as streaks and chevrons in the finished product. Some prior jet interlacing processes frequently rely on multiple tensions applied to the yarn components, which tensions tend to vary over time, requiring constant attention to the tension mechanisms. If it is desired to vary the tensions on several components to cause multiple colors to stand out randomly, making these tension changes quickly enough to prevent directional carpet appearance is extremely difficult. Other prior jet interlacing techniques rely on such a high degree of blending that the aesthetics of moresque or berber are impossible to achieve.
U.S. Pat. Re. 31,808 to London, Jr., et al. describes yarns having pronounced variations in linear density in a yarn where an effect component yarn is wrapped around a core yarn.
U.S. Pat. No. 4,343,146 to Nelson discloses a process for producing heather BCF yarns in which a first yarn is entangled with at least one second yarn which is precolored or differentially dyeable with respect to the first yarn. The second yarn contains frequent periodic short relatively compact regions of high filament entanglement. When the first and second yarns are textured according to the described Nelson process, the compact regions of the second yarn are substantially free from commingling with filaments of the first yarn. Between the compact regions are bulky or relatively open regions of textured first and second yarns.
Several co-owned patents such as U.S. Pat. Nos. 4,894,894; 4,993,130; and 5,040,276 have specified uniform blending to ensure a streak-free carpet. The resulting products of solution dyed or differentially dyeable BCF are intimately mixed heathers, not moresque or berber yarns. Otherwise, stria caused by sections of unblended fibers give the carpet directionality and can cause streaks. Sufficient blending of heavy denier yarns (greater than 10,000) is often impossible if the component colors are highly contrasting.
U.S. Pat. No. 5,148,586 to Coons III describes a-continuous filament yarn product which is interlaced to form a uniform linear density yarn product. The yarn product is formed from at least two component yarns which are differently colored or dyeable with respect to each other. The accent, or color point yarn is entangled, and the two yarns are commingled between compact regions in the color-point yarn, but substantially free from commingling in the compact regions of the color-point yarn to produce a random moresque appearance. This manner of constructing BCF heather yarn does not produce suitable results when the base yarn and the accent yarn are highly contrasting because the sections between the color points will be striated.